Complex numbers

Hello, I have this complex number that I need to convert to polar coord represntation:
z = 1 + j;
the answer is sqrt(2)e^-j45
(45 is degrees).
The part I don't undestand is negative before j45, since a and b are positive, I assumed it's in the first quandrant of Im/Re plane, and if the reference point for theta is real axis postive direction I do not see why there is a "-".
Thanks for explanation.

Thanks, that makes me happier
But generally, the "-/+" of the angle depends on the position of a and b in the im/real plane, so theta is counted from positive direction of real axis, like usually in geometry ... is it right?